1. Field
The present inventive concepts relate to a radio frequency identification (RFID) interrogator and a method of operating the same, and more particularly, to an RFID interrogator for automatically setting or changing a bandwidth of a receiving signal from a tag and a method of operating the same.
2. Description of Related Art
FIG. 1 is a schematic diagram of a conventional RFID system. Referring to FIG. 1, the RFID system includes an interrogator (or a reader) 1 and a tag 2. The interrogator 1 reads or writes information stored in the tag 2 using a radio frequency. The interrogator 1 transmits a transmission signal Tx, which is a continuous wave (CW) including a predetermined command, to the tag 2. The tag 2 is provided with power from the transmission signal Tx and backscatters a signal Rx including predetermined information to the interrogator 1.
FIG. 2 is a graph showing the power and the bandwidth of the signals Tx and Rx illustrated in FIG. 1. Referring to FIGS. 1 and 2, while the transmission signal Tx is provided has high power but narrow bandwidth, the backscattering signal Rx is provided with low power but wide bandwidth.
For such an RFID system including a plurality of interrogators, various regulations have been defined in order to minimize interference between the interrogators and some efforts have been made to reduce channel interference using listen-before-talk (LBT) or hopping technique. However, since the backscattering signal Rx has very low power and hardly affects other wireless devices, such regulations or efforts have been made to reduce interference between transmission signals Tx, but have not addressed the backscattering signal Rx. Moreover, when the bandwidth of the backscattering signal Rx is increased when increasing a data rate, the receiving performance of an interrogator may be reduced due to interference from other devices, even though the interrogator does not affect other interrogators.
For this reason, the backscattering signal Rx conventionally has a fixed bandwidth that is at a state in which maximum interference may occur, regardless of a channel environment.